The announcement shed no further light on the death of the man, Urooj Khan. Authorities dug up his body last month in hopes of learning more, but the tissue had decomposed too badly to yield any additional clues, the medical examiner said.

Dr. Stephen Cina, medical examiner for Cook County, said that blood tests after the exhumation confirmed the finding. He also told reporters that he could not conclude how the cyanide was administered. It can be swallowed, inhaled or injected.

Khan, an Indian immigrant, came to Chicago in the 1980s and opened his own dry-cleaning shop in 2004. He owned three by the time of his death, in addition to five condominiums that he rented out.

He bought the lottery ticket at a Chicago 7-Eleven last June, scratched it off and said later that he was so giddy at what he found that he tipped the clerk $100.

Illinois Lottery via Reuters

Urooj Khan of Chicago is pictured holding his winning $1 million lottery ticket in this photo from the Illinois Lottery.

He died in July, at 46, one day after the state of Illinois cut him a check for $424,449, his winnings on the ticket after he chose a one-time payment and after subtracting taxes. He threw up blood the same day, a relative said.

The medical examiner first ruled that Khan had died from natural causes. Six months later, authorities said they had conducted further tests — at the request of a relative they did not name — and determined it was cyanide poisoning.

Since Khan’s death, his widow has battled with his brother and sister over control of his estate, including the winnings, documents published by NBCChicago.com show. The widow, Shabana Ansari, denies removing money from the estate.

Ansari told The Associated Press last month that her husband had no enemies.

“I was shattered. I can’t believe he’s no longer with me,” she said.

Police are still investigating.

Cina said that “non-specific residue” was also found in Khan’s stomach. He said that it was possible cyanide had seeped into the tissue as well, but that cyanide has a short half-life and might have dissipated past the point of detection.